Microsoft filed suit against the DVR maker on Tuesday for infringing on two Microsoft patents as a way of defending its partner, AT&T, which is currently involved in a legal dispute with TiVo over the same technology. TiVo sued AT&T and Verizon in August over the "time warping" function in both companies' digital video services. AT&T uses Microsoft's video platform for its U-Verse TV IPTV service.

It's because AT&T is Redmond's biggest customer for that video technology that it has opted to come to AT&T's defense.

But Microsoft said it's "open to resolving this situation through an intellectual property licensing agreement, and we have initiated discussions to engage TiVo in negotiations," according to a statement from the company Wednesday.

TiVo shrugged off the tech heavyweight's entrance into the legal fight in a statement Wednesday: "Microsoft's recent legal actions ... do not bear on whether the AT&T products and services that are the subject of TiVo's complaint infringe the patents asserted by TiVo. Rather these actions are part of a legal strategy to defend AT&T. We remain confident in our position that AT&T will be found to infringe on the TiVo patents asserted."

It's not clear how Microsoft's entrance will help or hurt AT&T, especially since TiVo has already played this game and won. The strategy it is currently pursuing against AT&T and Verizon over the time-warp function is the same that won it damages of $103 million from EchoStar/Dish Network last year.

About the author

Erica Ogg is a CNET News reporter who covers Apple, HP, Dell, and other PC makers, as well as the consumer electronics industry. She's also one of the hosts of CNET News' Daily Podcast. In her non-work life, she's a history geek, a loyal Dodgers fan, and a mac-and-cheese connoisseur.
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